Box extension ring



Dec 23, 1952 1, APPLETON 2,622,756

BOX EXTENSION RING 7 Filed Oct. 6 1950 INVENTOR. arthur A. yyaleton Patented Dec. 23, 1952 UNITED STATES PATENT OFFICE BOX EXTENSION RING 7 Arthur I. Appleton, Northbrook, Ill. Application October 6, 1950, Serial No. 188,748

4. Claims. 1

The present invention relates generally to the field of electrical boxes and fittings but more specifically to a novel extension ring for attachment to a junction box or the like to increase the depth of the same.

The principal object of the invention is to provide a box extension ring having a novel and improved means for securing the same to a junction box or the like.

Another object is to provide a box extension ring of simple, rugged construction and which will be susceptible of rapid installation and economical manufactureon a mass productive basis.

Other objects and advantages will become apparent as the following description proceeds, taken in the light of the accompanying drawing, wherein:

Figure 1 is a perspective view showing an illustrative box extension ring embodying the invention and mounted in position upon a conventional junction box.

Fig. 2 is a plan view of the illustrative ring and box shown in Fig. 1.

Figs. 3 and 4 are enlarged fragmentary vertical sectional views taken in the plane of the line 4--4 in Fig. 2 and illustrating sequentially the manner in which the extension ring is installed upon the junction box.

Fig. 5 is a perspective View detailing the bottom of the illustrative box extension ring shown in Fig. 1.

While the invention is susceptible of various modifications and alternative constructions, a preferred embodiment has been shown in the drawing and will be described below in considerable detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but on the contrary, the intention is to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more specifically to the drawing, the invention is there shown embodied in an illustrative extension ring as adapted in the present instance for attachment to the open end of a junction box 2 I. The latter in this case happens to be of stamped or drawn sheet metal construction. Its side Walls define substantially a square when viewed in plan and are provided with one or more knockout apertures l2 and their corresponding removable plugs l4. At diagonally opposite corners, the top edges l5 of the junction box II have integral therewith inturned lugs 16.

These are drilled and tapped for the reception of mounting screws 18 normally used for attaching a cover to the box ll.

The extension ring I!) is polygonal in form and in the present instance corresponds in overall shape to the junction box H with which it is to be used. Thus the ring I!) comprises a side wall structure l9 terminating in a top edge '20 similar to the edge l5 of the box II and provided with a pair of diagonally opposed, inturned mounting lugs 2|. The latter are similar to the lugs l6 of the junction box, being adapted to threadedly receive one or more cover mounting screws. At the bottom, the side wall structure l9 terminates in an inturned flange 22 which is preferably integral with the wall structure It. The flange 22 has a curved external surface which seats readily upon upper edge I5 of the junction box wall and also upon the screw lugs I6 of the junction box.

Provision is made for effecting attachment of the ring In to the box H with security, ease and rapidity. In furtherance of such objective, the bottom flange 22 is fashioned with a pair of dimetrically opposed corner webs 24, 25, spaced alternately with the inturned mounting lugs 2|. The corner webs 24, 25 are respectively provided with alined and diagonally extending screw slots 26, 28, each of appropriate width to accommodate the shank of a mounting screw IS. The slot 26 terminates in its corresponding corner Web 24. The slot 28, however, extends completely through its corner web 25 and terminates in a laterally enlarged extension 29 located up in the side wall structure 19 of the ring ll]. As clearly indicated in Figs. 3, 4 and 5, such construction defines a pair of integral lugs 30 spaced the width of the slot 28 and upstanding above the general plane of the flange 22.

The manner in which the ring It) may be attached to the box I I will be readily understood upon reference to Figs. 2, 3 and 4. Assuming the mounting screws l8 of the box H to be in approximate mid-position on the lugs IS, the first step in installation of the ring it is to place it on the upper edge of the box H in offset relation with the same and with the diagonal axis of the screw slots 26, 28 in alinement with the box diagonal running between the screws [8. As a result of contact between the corner webs 24, 25 and the lugs I6, as well as contact between the upper edge [5 of the box and points on the underside of the ring NJ at the corners remote from the corner webs, the ring I0 is maintained level :at this time. The next step in installation involves moving the ring it) along the diagonal axis of the slots 26, 28 from the position indicated in Fig. 3 to the position indicated in Figs. 2 and 4. This results in seating the ring in centered and overlying relation with respect to the box H. Moreover, without tightening either of the screws IS, the ring I0 is confined against movement in any direction other than along the diagonal axis of the slots 26, 28. As soon as the screw l6 adjacent the slot 28 (shown in lower right-hand corner of Fig. 2 and right-hand end of Figs. 3 and 4) is tightened below the restraining lugs 30, the ring l0 becomes positively attached to the box I I. To make the attachment completely secure, the screws I8 are, of course, tightened in the lugs l6 until their heads accost the respective underlying portions of the corner webs 24, 25.

Upon reflection, it will be noted that the structure described herein not only permits rapid installation of the extension ring [0, but, in addition, provides a very positive and .foolproof attaching arrangement. Once the ring ii is slid into centered position on the box I l, the ring can be locked in place with very little tightening of the screws l8. Even if the screws l8 should loosen up slightly, the ring I0 cannot slide out of position due to the locking action of the restraining lugs and the adjacent one of the screws I 8.

Iclaim as my invention:

1. Asan article of manufacture, a box extension ring comprising the combination of a po1ygo nal side wall structure having one or more knockout apertures therein, a base flange integral with said wall structure, a pair of corner webs integral with said base flange and situated at diagonally opposite corners on said ring, each of said corner webs having a screw slot running in the direction of the diametrical axis of said webs, each said screw slot being adapted to constrain said ring against movement in directions other than along said diametrical axis, one of said slots having a laterally enlarged extension projecting into the side wall structure of said ring.

2. As an article of manufacture, an extension ring for attachment to an electrical junctionbox with its sides in substantially coplanar relation with those of the box, said ring comprising the combination of a polygonal side wall structure having one or more knockout apertures therein, an inturned base flange fixed to said wall structure, said base flange having a pair of alined screw slots coaxial with one of the diagonals of said-side wall structure and located in diametrically opposed corner regions of said ring, one of said slots terminating in a laterally enlarged extension projecting into the side wall structure of said ring, said extension being of suificient width to clear the head of a mounting screw.

3. An extension ring for attachment to electrical junction boxes and the like, said ring comprising the combination of a rectangular side wall structure having knockout apertures therein, said side wall structureterminating at the top in a pair of cover mounting screw lugs, said side wall structure terminating at the bottom in an inturned ledge at the base of said ring, web portions of substantially triangular form integral with said ledge and located at diagonally opposite corners of said ring, each of said web portions having a diagonally extending screw slot, one of said screw slots extending into the angular corner of said side wall structure and terminating in a laterally enlarged portion of generally circular shapefor clearing the mounting screw of a junction box as said ring is slid into position thereon.

4. An extension ring for electrical junction boxes and the like, said ring comprising, in combination, a side wall structure, an inturned base flange fixed to said side wall structure, said flange being formed with a pair of diagonally alined slots, one of said slots terminating short of said side wall structure, the other of said slots extending upward along one corner of said side wall structure and terminating in a laterally enlarged portion in said side wall structure, the upward extending portion of said other slot having edges disposed adjacent said laterally enlarged portion, said edges constituting restraining lugs adapted to accost the head of a mounting screw when the same is substantially against said flange and thereby to preclude detachment of said ring from the junction box.

ARTHUR I. APPLETON.

REFERENCES CITED The following references are of record in the X file of this patent:

UNITED STATES PATENTS 

